Liquid-fuel pump



Jan. 15, 1929.

H. JUNKERS QUID FUEL PUMP Original Filed Feb. 24, 1927 Patented Jan. 15,1929 UNITED STATES 1,699,194 PATENT OFFICE.

HUGO JUNKEBS, 0F DlESSAU, GERMANY.

LIQUID-FUEL PUMJP. I

Original application filed February 24, 1927, Serial No. 170,693, and inGermany February 88, 1926. Divided and this application filed November25, 1927. Serial No. 235,701.

My invention relates to fuel pumps which are especially ada ted for usein connection surplus of liquid into an exhaust pipe or directly intothe atmosphere by means of special members controlled by the pump pistonmovement.

The present-invention relates to an improved arrangement, which providesfor a particularly complete removal of air from the pump and for a nickseparation of the air from the surplus of fuel escaping together withthe air, soasto render this part of the fuel directly available forbeing sucked into thepump.

According .to this invention I obtain this by placing the exhaust memberfor the surplus of fuel in communication with a fuel storage chamberarranged in close vicinity to the pump and having the fuel storedtherein in practically currentless condition. The communication iseffected by means of a pipe or conduit of short length and littleresistance. The air thus introduced into the supply offuel can escapefreely either into the atmosphere or, if the storage chamber is closed,it can easily be exhausted by suitable means, preferably the suctionconduit of the pump is also connected with the storage chamber, so thatthe surplus of fuel removed by the pump can at once be sucked in againby the pump. The exhaust member for the surplus fuel and for the air canhave any suitable form and may be a valve or a conduit controlled by thepump piston. This member is preferably connected with the highest partof the piston chamber, so that the air sucked into this chamber canescape directly whenever the exhaust member is opened.

The communication between the pump chamber and the fuel supply for thepurpose of separating the air can also be effected by means of thesuction member and suction passage itself, but as a rule I preferemploying for this purpose a separate conduit in order to (prevent air,which has already been separate out, from entering the pump againtogether with the fuel sucked in. In any case the passage for removingthe air should be as short and wide as possible.

I further found it advantageous for the escape ofthe air conveyed intothe storage chamber, 1f the liquid level in this chamber is keptconstant relative to the pum so that always the same conditions prevailfbr the air separation. The keeping constant of the liqu1d level can forinstance be effected by means of a float acting on an inlet valve or bymeans of an overflow.

A further means of removing the air separated out from the pump consistsin washing it away by a liquid current, for instance by supplying anexcess of fuel to the fuel pump by means of an auxiliary pump, this fuelin excess being utilized for carrying along the air separated from thefuel pump up to a point Where it can easily escape into the atmosphere.This arrangement offers the advantage that no open liquid surfaceis,required near the fuel pump, which is frequently desirable in view ofdanger of fire.

In the drawings affixed to this specification and forming part thereofpumps embodying my invention are illustrated diagrammatically by way ofexample.

In the drawings Fig. 1 illustrates a pump having means for removing airfrom the fuel,

Fig. 2 illustrates a similar pump in which the piston is inverted withrespect to Fig. 1,

Fig. 3 illustrates a pump in which the cylinder is provided with alongitudinal groove, the piston being inverted as in Fig. 2.

In all the figures, 1 is the piston, 2 is the cylinder, 3 is the suctionport, 4:.is the delivery valve, and 5 is the space or working chamber ofthe cylinder in front of the piston.

The cylinder 2 is surrounded by a fuel supply tank which is open inFigs. 1 and 2 and closed in Fig. 3. The suction passage 3 and the systemof passages for removing the air open into this tank, so that the airremoved from the pump is readily separated and-cannot be drawn back intothe system.

Referring first to Fig. 1, 42 and 43 are the central and radial bores ofthe piston and 44 is a discharge passa e in the cylinder wallcooperating with the bore 43. A. float 50 with a lever 51 and a valve 52controls the supply mulated in the space 5 may escape through thesechannels onto the stationary liquid contents of the tank 48, whence itescapes easily into the atmosphere. Removal of air is facilitated, it istrue,when the piston is inverted, that is when the space 5 is at thelower end of the piston as in Figs. 2 and 3 and not at the upper end, asin Fig. 1, but the air ma be removed with an upright piston as we 1 andnotwithstanding the fact that the opening of the interrupting passage 42is not at the highest point of the space 5. This is due to the fact thatthe mixture of fuel and air which enters into the space 5 at high speedunder the vacuum generated by the piston, forms with the air still inthe space 5 a sort of froth, part of which is discharged through theinterrupting passage.

' the discharge passage 44'.

In Fig. 2 the piston 1 is shown inverted, so that its lower face definesthe highest point of the s ace 5 and the bores 42 and 43 extend upwar sfrom this face and cooperate wit-h The delivery valve 4 is arranged atthe lowest point of the space 5, so that entrance of air into thedelivery system is effectively obstructed. The tank 48 is provided withan overflow 60, a supply 61 and a discharge pipe 62.

Fig. 3 illustrates a pump having a closed fuel tank and an invertedpiston 1. 3 is the suction passage and 72 is a channel in the pistonextending to the space 5 at the lower end of the cylinder and cominginto communication with the suction passage 3 when the piston makes itsdownward stroke, thus allowing the air accumulated in the space 5 toescape through the passages 72, 73 and 74 into the fuel tank 70. 80 is acirculating pump, the suction pipe 83 of which is connected with asupply tank 90 and the delivery pipe 81 of which opens into the closedtank 70. Fuel is supplied in excess and the overflow is returned to thesupply tank 90 through a pipe 82 and the air from the passage 3 iscarried along with the bverflow and separated in the tank 90 orconducted to any other point where it is permitted to separate from thefuel. A single circulating pump 80 may be provided in connection with aplurality of fuel umps and the fuel pumps may be connected in parallelor in series with respect to the fuel supply.

I wish it to be understood that I do not desire to be limited to theexact details of construction shown and described for obviousmodifications will occur to a person skilled in the art.

I claim 1. Fuel pump comprising a cylinder, a piston reciprocable insaid cylinder, one of adapted to be opened and closed directly by saidpiston for interrupting the delivery,

and a reservoir in close vicinity of said cylinder and containing asubstantially stationary body of liquid fuel in communication with saidconduit, said reservoir be' provided with escape means for the ventlngto atmosphere air entrapped by the pump.

3. Fuel pump comprising a cylinder, 9. piston reciprocable in saidcylinder, one of said parts being formed with a conduit adapted to beopened and closed in harmony with the movement of the pump piston forinterrupting the delivery, a fuel inlet in said cylinder and a reservoirin close vlcinity of said cylinder, containing a substantiallystationary body of liquid fuel in communication with said conduit andwith said inlet, said fuel constituting a liquid seal-for said inlet,and being maintained at a substantially constant level thereover, andmeans in said reservoir for venting the air entrapped in the pump toatmosphere.

4. Fuel pump comprising a cylinder and a piston reciprocable in saidcylinder, one of said parts being formed with a air venting conduitcommunicatin with the highest point of the working c amber of the pumpand adapted to be opened and closed directly by said piston forinterrupting the delivery and exhausting trapped air, said pistonbecoming active in its downward stroke, and a pressure valve in saidcylinder below said piston.

5. Fuel pump comprising a cylinder, a piston reciprocable in saidcylinder, one of said parts being formed with a conduit adapted to beopened and closed in harmony with the movement of the pump piston forinterrupting the delivery, a liquid container surrounding said pump andcommunicating with said conduit, spaced escape and supply passagesbetween the-cylinder and container normally below the liquid therein,and means for keeping said container permanently filled with liqui 6.Fuel pump comprising a cylinder having suction and outlet means, apiston reciprocable in said cylinder, one of said parts being formedwith a conduit adapted to be opened and closed in harmon with themovement of the pump piston or interrupting the delivery, a liquidcontainer in immediate 1,aee,194

through the latter.

inlet into communication with the working,

space of the pump during the delivery stroke, a reservoir in closevicinity of the pump and in communication with said inlet and containinga substantially stationary body of liquid fuel, and a separate escapepassage between the pump and the reservoir for venting air entrapped inthe In testimony whereof I afiix my signature.

HUGO JUNKERS.

pump to atmosphere 20

